Shell Oil Comapny

E.i. Dupont De Nemours and Company

Walter Dong

Donald W Stoutamire

Walter L Petty

James Laurel Buechele

Paul V Shaw

Thomas H Colby

Edward Lewis Nielsen

Peter S Friend

A process for the preparation of crystals of an adduct of a bisphenol with a phenol which comprises:

Method of purifying bisphenols

A process for the continuous purification of crude bisphenol which comprises (1) forming a single liquid phase comprising a hot mixture of crude bisphenol and water in a ratio substantially of from about 75% to about 85% weight of crude bisphenol to about 15% to about 25% weight water; (2) continuously feeding this mixture together with a stream of warm water to a first crystallization zone at a temperature sufficient to maintain a bisphenol-rich liquid phase, a water-rich phase and a crystalline phase comprising about 70% to about 95% of the total bisphenol in the mixture; (3) passing the three-phase mixture of bisphenol and water to a second crystallization zone operated at about 85.degree. C. to about 97.degree. C. until about 90% to about 99% of the total bisphenol is crystallized; and (4) recovering the purified bisphenol crystals.

Process for continuous purification of bisphenols

Preparation of certain optically-active alpha-hydroxynitriles or a mixture enriched therein comprises treating an aldehyde with hydrogen cyanide in a substantially water-immiscible, aprotic solvent in the presence of a cyclo(D-phenylalanyl-D-histidine) as a catalyst.

Preparation of optically active alpha-hydroxynitriles

Chiral aromatic cyanohydrins are prepared by treating an aromatic aldehyde with cyanide ions in the presence of an inert, aprotic solvent and a chiral cyclo(phenylalanyl-histidine) and an alcohol. The technique is especially useful for reducing the induction period when starting-up the process, increase the rate of reaction and to produce a product of increased enantiomeric selectivity.

Chiral cyanohydrination process

Enantiomeric selectivity is increased in chiral cyanohydrination of an aromatic aldehyde using a chiral cyclo(phenylalanylhistidine) catalyst by treating the (recycle) aldehyde to remove catalyst poisons or impurities which adversely effect enantiomeric selectivity.

Increasing enantiomeric selectivity in chiral cyanohydrination

A cyanohydrination catalyst for the preparation of alphahydroxynitriles from aldehydes and ketones comprises a solid cyclo(D-phenylalanyl-D-histidine) dipeptide having a non-crystalline or amorphous component.

Cyanohydrination of an aromatic aldehyde

Cyanohydrins or a solution thereof in an inert solvent are stabilized by treatment with organophosphoric acids.

Stabilization of cyanohydrins

A cyanohydrination catalyst for the preparation of alpha-hydroxynitriles from aldehydes and ketones comprises a solid cyclo(D-phenylalanyl-D-histidine) or cyclo(L-phenylalanyl-L-histidine) dipeptide having a non-crystalline or amorphous component.

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Houston, TX, United States of America

Walter Dong